EP2933322A1 - Method for the treatment of animal and vegetable waxes - Google Patents

Abstract

The invention relates to a process for the preparation of animal and vegetable waxes, in which the wax is mixed in the liquid state with a heated to a temperature above the melting temperature of the wax polar solvent for a defined period of time, then the mixture is cooled so far that the Wax solidifies while the solvent remains liquid and then the solvent is removed.

Description

The invention relates to a process for the preparation of animal and vegetable waxes.

Typical animal waxes are e.g. Beeswax or wool wax; among the vegetable waxes can be found e.g. Sugarcane wax, rice wax, carnauba wax or candelilla wax, just to name a few.

Waxes are found in a variety of different products. In the case of pharmaceutical products in particular, it is necessary and, in the case of cosmetic products, at least desirable that the waxes processed there satisfy the criteria defined in the Pharmacopoeia, i. contain as possible no harmful foreign substances.

A key problem in wax purity is the use of pesticides such as pesticides or insecticides. Sensitive products are therefore mostly made from vegetable or animal wax originating from areas where no pesticides are used.

However, this strategy is increasingly difficult to implement. In particular, the worldwide advance of various pests, such as those for bee mortality co-responsible Varroa mite, requires a nationwide use of pesticides, which will not stop at previously untouched areas or stop. It is therefore necessary to live with the fact that in the future there will be increasingly limited vegetable or animal waxes available that meet the requirements of the pharmacopoeia.

In the future, it will be increasingly necessary to prepare the available contaminated waxes so that they meet the purity requirements.

A known process for the purification of waxes is e.g. short path distillation under high vacuum. This process is used in particular for wool wax to remove enriched pesticides, with which the sheep are treated to prevent the spread of ticks. In this process, however, the proportion of free fatty alcohols in the wool wax is reduced and thus deteriorates the emulsion properties of the wool wax.

The object of the invention is to provide a method with which the proportion of undesirable harmful substances, in particular pesticides, can be gently reduced in wax.

This object is achieved by a method having the features of claim 1.

According to the invention it is provided that the wax to be purified is dissolved and then mixed with a polar solvent which has been heated to a temperature above the melting temperature of the wax. The mixture is kept at this temperature for a defined period of time. The period of time should be sufficient to allow the solvent to extract as quantitatively as possible from polar solvent-soluble substances contained in the wax. In order to improve the degree of extraction, it may in particular be provided that the mixture agitates, e.g. shaken or otherwise moved.

Then allowed to cool then the mixture until the wax has solidified again and then removes the liquid polar solvent.

Similar methods are known with which fragrances are extracted from eg beeswax. These accumulate in the polar solvent, usually ethanol, and can be isolated from it in the form of a so-called absolute used in the perfume industry.

Surprisingly, it has now been found by the Applicant that with the method according to the invention the usual pesticides enriched in the wax, such as e.g. Fluvalinate, Bromopropylate, DDT or Dicofol, just to name a few. This was surprising in particular because it was not to be expected that the usually fat-soluble pesticides could be extracted from the wax with polar solvents.

Polar solvents which can be used in the context of the invention are, in particular, alcohols. Preferably, ethanol is used. In the processing of higher melting waxes, it may also be necessary to use a higher boiling alcohol. Here, for example, Offer propanol.

As already mentioned above, the process is suitable for the treatment of all waxes whose sources may possibly come into contact with pesticides or pesticides.

The process exploits the insolubility of waxes in short chain alcohols such as methanol, ethanol, propanol and its isomers, butanol and its isomers.

In principle, the method in one embodiment can proceed as follows:

The wax to be purified is melted, mixed with alcohol in a ratio of wax to alcohol of, for example, 20% to 80% and extracted for a certain time (20 minutes - 60 minutes), for example with stirring. The mixture is then cooled with stirring to about 8 ° C, so that the wax precipitates quantitatively. It is advantageous that it is stirred constantly, so that a pumpable wax-alcohol slurry is obtained. This is then filtered off in a suitable device (filter press, clarifying centrifuge). The recovered alcohol is recycled and fed to the rectification. The filter residue is melted a second time and extracted a second time with fresh alcohol in the ratio 20% wax and 80% alcohol. It will take about 20-60 min. cooled again with stirring to about 8 ° C and then filtered off. The filter residue is distilled alcohol-free (eg vacuum distillation) and can as wax the corresponding Applications are supplied. The alcohol fractions are combined and can be rectified and used again next time.

Particularly addressed within the scope of the invention are waxes such as e.g. Beeswax, carnauba wax.

In the following, the invention will be explained in more detail with reference to some examples.

example 1 Cleaning beeswax

From a batch of beeswax about 20g of sample material were taken and determined therein by conventional methods, the content of fluvalinate. Fluvalinate can be considered as a lead substance, i. This substance is usually always present when a pesticide wax is loaded.

The result was 3.2mg / kg, well above the Pharmacopoeia limit of 0.05mg / kg.

From the same batch beeswax was prepared by the process according to the invention as follows:

50 g of beeswax were melted in a conical flask with reflux condenser and, after melting, 200 ml of ethanol were added. It was then 20 min. at 75-80 ° C further stirred. Thereafter, the reflux condenser was degraded and replaced with a KPG stirrer and cooled with vigorous stirring. To complete the crystallization, the wax-alcohol slurry was placed in the refrigerator at 4-8 ° C for about 60 minutes. Subsequently, the wax was separated from the ethanol via a suction filter. The wax was subjected to a second extraction as described under the above conditions. After separating wax and ethanol, the residual ethanol was evaporated or distilled off in vacuo.

In turn, the content of fluvalinate was determined, which was now 0.6 mg / kg. The processed wax was thus significantly less stressed than the untreated starting material. The value is still above the limit. Indeed this was just an experiment that basically demonstrated the suitability of the process for the removal of fluvalinate.

In further examples, it is shown that even higher degrees of purity can be achieved with the method according to the invention.

Example 2: Purification of wax doped with different pesticides

• Lindan: 0,36 ppm
• a-HCH: 0,32 ppm
• 2,4'- DDT: 0,36 ppm
• Coumaphos: 2,00 ppm
• Brompropylat: 2,16 ppm
• tau-Fluvalinat: 2,16 ppm

Here it should be shown that and how different pesticide types can be removed with the method according to the invention. For this purpose, an unencumbered beeswax was provided with the following pesticides in the respective concentrations:

• Lindane: 0.36 ppm
• a-HCH: 0.32 ppm
• 2,4'-DDT: 0.36 ppm
• Coumaphos: 2.00 ppm
• Bromopropylate: 2.16 ppm
• tau-fluvalinate: 2.16 ppm

50 g of beeswax doped in this way were melted in an Erlenmeyer flask with reflux condenser and, after melting, 200 ml of ethanol were added. It was then further stirred at 75-80 ° C for 45 min. Thereafter, the reflux condenser was degraded and replaced with a KPG stirrer and cooled with vigorous stirring. To complete the crystallization, the wax-alcohol slurry was dried for about 60 minutes. placed in the refrigerator at 4-8 ° C. Subsequently, the wax is separated from the ethanol via a suction filter. The wax was subjected to a second extraction as described under the above conditions. After separating wax and ethanol, the residual ethanol was evaporated or distilled off in vacuo.

• Lindan: 0,01 ppm
• a-HCH: 0,01 ppm
• 2,4'- DDT: < 0,01 ppm
• Coumaphos: < 0,03 ppm
• Brompropylat: < 0,1 ppm
• tau-Fluvalinat: < 0,1 ppm

Subsequent pesticide analysis showed the following result:

• Lindane: 0.01 ppm
• a-HCH: 0.01 ppm
• 2,4'-DDT: <0.01 ppm
• Coumaphos: <0.03 ppm
• Bromopropylate: <0.1 ppm
• tau-fluvalinate: <0.1 ppm

Thus, the process shows a good to very good removal of the various pesticides, in particular, the extension of the extraction time to 45 min. (compared to Example 1) has provided for an even better removal of the tau-fluvalinate.

Example 3 Purification of higher-melting wax doped with different pesticides

Here it should be shown that the method is also applicable to higher melting waxes.

• Lindan: 0,85 ppm
• a-HCH: 0,46 ppm
• 2,4'- DDT: 0,50 ppm
• Coumaphos: 3,00 ppm
• Brompropylat: 3,50 ppm
• tau-Fluvalinat: 3,10 ppm

For this purpose, an unloaded sunflower wax was provided with the following pesticides in the respective concentrations:

• Lindane: 0.85 ppm
• a-HCH: 0.46 ppm
• 2,4'-DDT: 0.50 ppm
• Coumaphos: 3.00 ppm
• Bromopropylate: 3.50 ppm
• tau-fluvalinate: 3.10 ppm

50 g of sunflower wax doped in this way were melted in an Erlenmeyer flask with reflux condenser and 200 ml of ethanol were added after melting. It was then further stirred at 75-80 ° C for 45 min. Thereafter, the reflux condenser was degraded and replaced with a KPG stirrer and cooled with vigorous stirring. To complete the crystallization, the wax-alcohol slurry was dried for about 60 minutes. placed in the refrigerator at 4-8 ° C. Subsequently, the wax was separated from the ethanol via a suction filter. The wax was subjected to a second extraction as described under the above conditions. After separating wax and ethanol, the residual ethanol was evaporated or distilled off in vacuo.

• Lindan: 0,07 ppm
• a-HCH: 0,04 ppm
• 2,4'- DDT: < 0,01 ppm
• Coumaphos: < 0,03 ppm
• Brompropylat: 0,2 ppm
• tau-Fluvalinat: 0,2 ppm

Subsequent pesticide analysis showed the following result:

• Lindane: 0.07 ppm
• a-HCH: 0.04 ppm
• 2,4'-DDT: <0.01 ppm
• Coumaphos: <0.03 ppm
• Bromopropylate: 0.2 ppm
• tau-fluvalinate: 0.2 ppm

The process thus shows a good to very good removal of the various pesticides even with higher melting waxes.

Example 4: Cold extraction of a beeswax with a large surface area

For this purpose, 50 g of sprayed beeswax having a particle size of about 300 .mu.m were admixed with 250 g of ethanol and a temperature of 40.degree. C. was set. Subsequently, at this temperature for 45 min. touched. After filtration, the filter residue was added again with 250 g of ethanol and it was again set to a temperature of 40 ° C. Subsequently, at this temperature for 45 min. touched. After filtration, the residue was freed from the remaining ethanol at 80-90 ° C.

The starting material was contaminated with the following pesticides: DDE, o, p- 0.056 ppm DDE, p, p'- 0.024 ppm DDT (total) 0.10 ppm DDT, o, p'- 0.078 ppm Dicofol, p, p- 0.45 ppm S421 0.11 ppm Tau-fluvalinate 4.0 ppm coumaphos 1.2 ppm

After extraction, the following values were determined: DDE, o, p- Traces <0.01 ppm DDE, p, p'- Traces <0.01 ppm DDT (total) 0.016 ppm DDT, o, p'- 0.016 ppm Dicofol, p, p- 0.11 ppm S421 not detectable Tau-fluvalinate 0.7 ppm coumaphos not detectable

The cold extraction with ethanol shows a significant reduction in all pesticides, which in some cases even goes below the detection limit.

Claims (3)

Process for the preparation of animal and vegetable waxes, in which the wax is mixed in a liquid state with a heated to a temperature above the melting temperature of the wax polar solvent for a defined period of time, then the mixture is cooled so far that the wax solidifies, while the solvent remains liquid and then the solvent is removed. A method according to claim 1, characterized in that it is the solvent is alcohol, especially ethanol or propanol and their isomers. Method according to one of claims 1 or 2, characterized in that the wax to be purified is beeswax, rice wax, carnauba wax.